/Engine/Source/Runtime/MovieScene/Public/Evaluation/MovieSceneEvaluationTrack.h
Called before this track is evaluated for the first time, or since OnEndEvaluation has been called
void OnBeginEvaluation ( [FPersistentEvaluationData](API\Runtime\MovieScene\Evaluation\FPersistentEvaluationData) & PersistentData, [IMovieScenePlayer](API\Runtime\MovieScene\IMovieScenePlayer) & Player ) const